Nonreciprocal topological kink-wave propagation in mechanical metamaterials

TL;DR

This paper demonstrates a nonlinear mechanical metamaterial that supports unidirectional, topologically protected elastic kink wave propagation through bifurcation-induced nonreciprocity, without relying on linear band topology or magnetic bias.

Contribution

It introduces a novel bifurcation-induced nonreciprocal lattice supporting robust kink wave transport, bridging bifurcation dynamics with topological-like mechanical functionality.

Findings

Supports unidirectional kink wave propagation immune to sharp bends

Uses a SineGordon type field to govern non-dispersive transport

Establishes a nonlinear route to topological-like mechanical behavior

Abstract

Nonlinear mechanical metamaterials can exhibit emergent transport phenomena that mimic topological protection without relying on linear band topology. Here, we realize a bifurcation-induced nonreciprocal lattice that supports robust propagation of elastic kink waves. Each unit is a prestrained, hinged-beam circulator that develops angular momentum bias during snap-through transitions between buckling states, producing an effective breaking of time reversal symmetry. Coupling such units into a hexagonal array yields a mechanically chiral network where localized soliton-like excitations propagate unidirectionally along interfaces and edges, immune to sharp bends. We demonstrate non-dispersive kink transport governed by a SineGordon type field whose effective bias encodes mechanical chirality. This framework bridges bifurcation dynamics and nonreciprocal transport, establishing a nonlinear route toward topological like mechanical functionality without magnetic or gyroscopic bias.